How zero dollar transactions are handled

Some payment gateways (such as Authorize.net, PayFlow, etc.) or credit card types (Visa, Mastercard, etc.) will decline a $0.00 transaction. To prevent the free order from being declined, the shopping cart software will submit the order to the payment gateway as a $1.00 "authorize-only" transaction. This will allow the payment gateway to validate the credit card.

The value of this authorization can be changed from $1.00 to a value that you specify. This can be done on the System Settings page, with the setting named Credit Card Validation Amount.

The "authorize-only" nature of the transaction means that the customer will never actually be billed for it. The gateway is just authorizing the card, making sure it is legit, and not charging it. The transaction will be listed in your payment gateway account records, but will expire after 30-90 days (depending on the gateway), and will remove itself from your gateway records after it expires. This authorization has no affect on your customer, order or subscription records in your store.